AL CAPONE - Dynamical constraints on regional climate projections of annual precipitation extremes
Stephan Pfahl, Patrick Pieper, Erich Fischer (ETH Zürich) und Donghe Zhu (ETH Zürich)
Jan 01, 2022 — Dec 31, 2024
On a large-scale average, annual extreme precipitation events intensify due to anthropogenic climate change. This intensification has been established on the basis of observations, theoretical considerations, and climate simulations. On a local scale, however, the evidence is, depending on the location, less conclusive because natural climate variability can exert an influence comparable to recent climate change on annual extreme precipitation events. The evidence is further complicated in some regions by large uncertainties in climate projections of annual extreme precipitation. The AL CAPONE project is conducted in cooperation with ETH Zurich and aims to dynamically constrain uncertainties in regional climate projections of annual extreme precipitation.
Atmospheric Dynamics of the most Extreme Precipitation Events over Europe and their Possible Changes in a Warming Climate
Stephan Pfahl, Florian Ruff
Oct 01, 2019 — Mar 31, 2023
BMBF project: ClimXtreme Heavy, large-scale precipitation events and associated floodings represent one of the greatest natural hazards for society in Europe. The rarity of these most extreme precipitation events makes systematic scientific investigations difficult. The processes behind such ...
Effects of Latent Heat Release on Atmospheric Blocking: process understanding, model evaluation and potential impacts of climate change
In Cooperation with ETH Zürich
Stephan Pfahl, Daniel Steinfeld
Recent research has shown that latent heat release during cloud formation in ascending air streams is a crucial process for the formation of atmospheric blocking that is not probably accounted for in current blocking theories, might lead to model deficiencies in the representation of blocking, and can contribute to future changes in blocking occurrence due to climate warming. In this project, we aim to improve our understanding of this linkage between latent heat release and blocking with the help of Lagrangian diagnostics applied to reanalysis data, global climate simulations and simulations of individual blocking cases with artificially modified latent heat release.
Persistence/abrupt changes in extreme weather events, their responsible processes, and relationships change in a warmer climate
Stephan Pfahl, Kalpana Hamal
Jan 08, 2022 — Jan 08, 2026
People can directly perceive day-to-day (DTD) temperature variation, which measures rapid weather variability and affects human health and the ecosystem significantly. The project aims to explore the historical and future conditions of DTD temperature variations and the persistence/cause of these variations. For this purpose, observation and ensemble simulations of the current and future climate will be examined at seasonal timescales.
The Dynamics of Heat Waves
Stephan Pfahl, Lisa Schielicke
The intensification of heat waves is one the most certain and, at the same time, most impact-relevant consequences of anthropogenic climate warming. However, an accurate assessment of the magnitude of this intensification has to take into account potential changes in the atmospheric circulation patterns associated with heat waves. We use a combination of Eulerian circulation feature analyses and Lagrangian, trajectory-based diagnostics to investigate future changes in heat waves as simulated by climate models from a dynamical perspective.
The Interaction between Fronts and Convective Cells in the Midlatitudes
Stephan Pfahl, Lisa Schielicke, George Pacey, Rupert Klein (Institut für Mathematik) Daniel Baum (Zuse Institut Berlin)
Mar 16, 2020 — Jun 30, 2026
Scaling cascades in complex systems. Atmospheric convection is a key process in the formation of certain atmospheric hazards such as extreme precipitation, hail and lightning. Convection is controlled by the interaction of various spatial and temporal scales: the synoptic scale, the mesoscale ...
Cyclone Dynamics in a Warming Climate
Stephan Pfahl, Edgar Dolores Tesillos
Jun 01, 2018 — Jun 01, 2022
Extratropical cyclones are an integral component of midlatitude weather variability and can cause extreme rainfall and windstorms with substantial effects on society. Nevertheless, projections of future changes in cyclone frequencies and intensities are associated with large uncertainties. This project aims to better understand the dynamical processes potentially affecting future cyclone occurrence in the North Atlantic and Mediterranean region. To this end, cyclones in large ensemble simulations of present-day and future climate are investigated based on a potential vorticity perspective and using trajectory analyses.
NOTE: the completed projects are here.